(1) The control of the galactose operon in E. coli is studied as a model system for gene regulation. We have demonstrated that the regulation of this operon is exerted by two overlapping promoters P1 and P2. The cyclic AMP receptor (CRP) and cyclic AMP (cAMP) activate only P1. P2 is repressed by CRP and cAMP and is probably subject to another regulatory mechanism. We have determined the nucleotide sequence of the entire regulatory region for the wild type gal operon and the base changes in several mutants in this region. This operon constitutes an excellent model system for the study of complex genetic regulation. (2) In collaboration with Dr. Ira Pastan we have demonstrated that the levels of translatable mRNA for two large extracellular proteins, the Cell Surface Protein and Collagen, are considerably reduced in transformed cells. These two proteins play an important role in the cellular interactions between normal cells. We have also shown that the copy number of collagen mRNA sequences is severely reduced in transformed cells. We have constructed several plasmids containing portions of the collagen genes. We are studying the cause for the reduction in collagen mRNA in transformed cells and are investigating the genomic organization of the collagen genes.